Floor polishing and scrubbing machine

ABSTRACT

IN ADDITION TO THE CONVENTIONAL FLOOR SCRUBBING BRUSH OR PAD, A SMALLER PRESSURE ELEMENT IS PROVIDED TO EXERT LOCALIZED CONCENTRATED PRESSURE. SUCH CONCENTRATED PRESSURE ELEMENT MAY BE A SMALL RESSURE HEAD LOCATED TO BE PRESSED DOWNWARD BY A RECIPROCABLE ROD EXTENDING THROUGH THE HOLLOW MOTOR SHAFT OR THROUGH THE HOLLOW CENTER OF AN ANNULAR BRUSH. ALTERNATIVELY, SUCH CONCENTRATED PRESSURE ELEMENT CAN BE AN ANNULAR RING SPACED FROM THE BRUSH CENTER. THE RING OR HEAD CAN ENGAGE A FLEXIBLE DIAPHRAGM WHICH CAN PRESS A PAD AGAINST THE FLOOD. THE CONCENTRATED PRESSURE ELEMENT CAN BE DRIVEN TO ROTATE WITH THE CONVENTIONAL BRUSH OR INDEPENDENTLY OF IT. ALSO, THE CONCENTRATED PRESSURE ELEMENT CAN BE MOUNTED FROM THE POILISHING AND SCRUBBING MACHINE BODY INDEPENDENTLY OF THE CONVENTIONAL BRUSH OR IT CAN BE MOUNTED ON AND REMOVABLE WITH THE BRUSH. A BOWDEN WIRE, A FLUID JACK, AN INCLINED WEDGE, THRUST LINKAGE OR AN INFLATABLE PRESSURE MEMBER CAN EFFECT DOWNWARD PROJECTION OF THE CONCENTRATED PRESSURE ELEMENT. LIQUID WAX OR SOAP CAN BE DISPENSED BY MANUAL CONTROL FROM A RESERVOIR CARRIED BY THE HANDLE THROUGH A DUCT TO THE FLOOR-ENGAGING BRUSH OR PAD.

June 8, 1971 R. 'r. DAVIS FLOOR POLISHING AND SCRUBBING MACHINE 7Sheets-Sheet 1 Filed Sept. 3. 1968 3 AMI, m 2

I may? I %AV% 5 /2 35 5 4 2 BY a, ,f4 ,-@I K Arrows 5r June 8, 197-] R.T. DAVIS FLOOR POLISHING AND SCRUBB ING MACHINE 7 Sheets-Sheet z FiledSept. 5. k68

June 8,1971 R. T. DAVIS moon rousnme AND scnusame MACHINE 7 Sheets-Sheet5 Filed Sept. 5. 1968 June 8, 1971 R. T. DAVIS 3,583,011

FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5. 1968 7 Sheets-Sheet27 a 52 ll I 'IIIIIIIIIIIIIIIA o l I I 6 I Be -4&7 Z 2 Hal.

INVIV'IN'IUR, @9866) 77 DAV/5 June 8,, 1971 DAVls 3,583,017

FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5. 1968 TSheets-Sheets Mme 8, 1971 R. "r. DAVIS 3,583,017

FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5, 1968 7 Sheets-Sheet6 w M 1 a A45 M 7 g, 7 ,4; w

BY M -M A rrOuPA/EV R. T. DAVIS FLOOR POLISHING AND SCRUBBING MACHINEFiled Sept. 5, 1968 7 Sheets-Sheet '7 NVIZ Roaeer .7:

United States Patent Oifice 3,583,017 Patented June 8, 1971 3,583,017FLOOR POLISHING AND SCRUBBING MACHINE U.S. CI. -98 11 Claims ABSTRACT OFTHE DISCLOSURE In addition to the conventional floor scrubbing brush orpad, a smaller pressure element is provided to exert localizedconcentrated pressure. Such concentrated pressure element may be a smallpressure head located to be pressed downward by a reciprocable rodextending through the hollow motor shaft or through the hollow center ofan annular brush. Alternatively, such concentrated pressure element canbe an annular ring spaced from the brush center. The ring or head canengage a flexible diaphragm which can press a pad against the floor. Theconcentrated pressure element can be driven to rotate with theconventional brush or independently of it. Also, the concentratedpressure element can be mounted from the polishing and scrubbing machinebody independently of the conventional brush or it can be mounted on andremovable with the brush. A Bowden wire, a fluid jack, an inclinedwedge, thrust linkage or an inflatable pressure member can effectdownward projection of the concentrated pressure element. Liquid wax orsoap can be dispensed by manual control from a reservoir carried by thehandle through a duct to the floor-engaging brush or pad.

This application is a continuation-in-part of application Ser. No.546,712, filed May 2, 1966 for Floor Polishing and Scrubbing Machine,now abandoned. This invention relates to a machine for polishing andscrubbing floors such as for polishing wax on hardwood floors or floorsof asphalt tile or scrubbing floors of asphalt tile or carpets, forexample. The machine in general is of conventional type, including acasing supporting a motor in a position with its axis upright and anannular brush received in a recess in the lower portion of the casingwhich is driven rotatively by the motor.

The principal object of the present invention is to enable such a floorpolishing and scrubbing machine to be used more effectively and easilyby applying liquid wax or detergent within the hollow central portion ofthe annular brush so that it will be trapped against escaping withoutbeing operated on by the brush.

An additional object is to enable concentrated cleaning pressure to beexerted on a small area within the annulus of the usual brush and toenable such pressure to be controlled both as to duration and degree atthe will of the operator.

It is also an object to provide not only concentrated pressure whendesired, but also pressure of a surfacecontacting element which can berotated rapidly in contact with a floor surface while such pressure isexerted on it.

Despite the provision of an element for applying concentrated localpressure it is an object to enable liquid detergent or wax to besupplied within the hollow of an annular floor polishing and scrubbingmachine brush and possibly onto the element which exerts theconcentrated local pressure on the floor surface.

A further object is to provide a concentrated pressure element which iscarried by a removable brush so that a conventional floor polishing andscrubbing machine could be converted readily principally by substitutinga different removable brush and making minor modifications in the bodyof the machine.

These objects can be achieved by modifying the structure of aconventional floor polishing and scrubbing machine of the type describedabove in providing a hollow motor drive shaft through which liquid waxor detergent can be supplied to the hollow in the center of the brush,or which will receive a rod which can be pressed lengthwise downward toexert pressure on a pres sure head located within the annulus of thebrush. Such pressure rod can be hollow to enable liquid detergent or Waxto be supplied through such pressure rod onto the concentrated pressureelement. In addition, an auxiliary motor can be connected to the upperend of the pressure rod for rotating it. In such case, a pressure headindependent of the conventional annular brush is mounted on the lowerend of the pressure rod so that it can be rotated at a speed higher thanthe conventional brush while downward pressure is being exerted on thepressure rod. Controls for exerting downward pressure on the rod fordispensing liquid detergent or Wax and for controlling the energizationof the auxiliary pressure rod rotating motor can be mounted on thehandle customarily provided on a floor polishing and scrubbing machinefor manipulating it. Alternatively, the concentrated pressure elementcan be built into a removable brush head so that such element can beprovided as a feature of a removable brush and actuating means for suchelement can be applied to the body with minimum modification of themachine body. Such construction is of a type which will enable aconventional fioor polishing machine to be converted into a machineequipped with the present invention.

FIG. 1 is a top perspective of a fioor polishing and scrubbing machineincorporating the present invention. FIG. 2 is an enlarged sideelevation of such machine with parts broken away and showing parts inretracted position, and FIG. 3 is a similar view with additional partsbroken away and showing parts in projected operative position. FIG. 4 isa fragmentary top perspective of the upper portion of the machine.

FIG. 5 is a top perspective of the upper portion of the machine similarto FIG. 4 but showing a somewhat modified construction.

FIG. 6 is a top perspective of another form of the floor polishing andscrubbing machine, and FIG. 7 is a side elevation of such machine on anenlarged scale with parts broken away.

FIG. 8 is a top perspective of still another form of the machine, andFIG. 9 is a side elevation of such machine on an enlarged scale withparts broken away.

FIGS. 10, 11, '12 and 13 are side elevations with parts broken away ofdiiferent types of floor polishing machines in which the invention hasbeen incorporated to provide a central concentrated pressure element.

FIG. 14 is a fragmentary vertical section through the lower portion of afloor polishing and scrubbing machine equipped with a different type ofbrush and concentrated pressure structure.

FIG. 15 is a side elevation of a floor polishing and scrubbing machinehaving a movable brush carrying a concentrated pressure element and FIG.16 is a horizontal section through such machine taken on line 16-16 ofFIG. '15. FIG. 17 is a detailed vertical section through a portion ofthe brush mechanism of such machine taken along line 17-17 of FIG. 15.

FIG. 18 is a side elevation with parts broken away corresponding to FIG.15 but with parts shown in a different relationship and FIG. 19 is adetailed vertical section corresponding to FIG. 17 but with parts shownin the different relationship of FIG. 18, such view being taken alongline 1919 of FIG. 18.

FIG. 20 is a bottom perspective of a component of the machine shown inFIGS. 15, 16 and 18.

FIG. 21 is a fragmentary vertical section through a portion of a floorpolishing and scrubbing machine having a structure somewhat similar tothat of the machine shown in FIGS. 15, 16 and 18, but of modified type.

FIG. 22 is a side elevation with parts broken away of a floor polishingand scrubbing machine having another type of concentrated pressureelement incorporated in a removable polishing and scrubbing head. FIGS.23 and 24 are fragmentary vertical sections through a portion of thepolishing and scrubbing head showing parts in different relativepositions. FIG. 25 is a top perspective of the structure shown in FIGS.23 and 24 with parts broken away. FIG. 26 is a vertical section taken online 2626 of FIG. 24.

FIGS. 27 and 28 are fragmentary vertical sections correspondingrespectively to FIGS. 23 and 24 but showing a different type ofactuating mechanism for a concentrated pressure element. FIG. 29 is adetail top perspective of a portion of the structure shown in FIGS. 27and 28.

FIGS. 30, 31 and 32 are detail vertical sections through a portion of afloor polishing and scrubbing machine gen erally of the type shown inFIG. 22 but embodying a different type of concentrated pressure elementand actuating mechanism, the several figures showing differentcomponents of the mechanism.

FIGS. 33 and 34 are vertical sections through the central portions offloor polishing and scrubbing machines showing floor polishing andscrubbing machine structures for dispensing liquid which differ somewhatfrom each other and which differ considerably from the types of machineillustrated in the preceding figures. FIG. 35 is a fragmentary verticalsection taken on line 35-35 of FIG. 34.

FIGS. 36 and 37 are vertical sections through floor polishing andscrubbing machines generally like those shown in FIGS. 33 and 34 buthaving somewhat different structures and structures which differ to someextent from each other.

FIG. 38 is a vertical section through a portion of a floor polishing andscrubbing machine of a different type constructed both to applyconcentrated pressure and to dispense liquid, and FIG. 39 is an enlargedsimilar section of a smaller portion of the machine with parts in adifferent relationship.

A conventional floor polishing and scrubbing machine to which thepresent invention may be applied includes a casing 1 encircling anannular brush 2 which is received in a downwardly opening recess 3 ofthe casing. Such brush is removable, being secured by a disengageablebrush-attaching coupling 4 to a brush-rotating driving head within thecasing. Such casing supports an electric motor 6 in a position with itsrotative axis upright and concentric with the brush 2. Such motor isconnected to the brush through speed-reducing planetary gearing 7 bywhich the driving head 5 is rotated at a speed considerably less thanthe rotative speed of the motor.

The floor polishing and scrubbing machine is guided manually formovement over the floor by a handle 8 inclined upwardly from the casing1 and having transverse handle grips 9 on its upper end. The machine canbe supported by retractable wheels when in the lowered position toenable the machine to be wheeled from place to place with little or nocontact of the brush 2 with the floor. When the machine is in use forpolishing or scrubbing purposes, however, the wheels 10 will be swungupward so that the machine rests on the brush 2 as shown in FIG. 2. Insuch event the weight of the machine assists the polishing or scrubbingaction of the brush.

The polishing or scrubbing action of brush 2 is accomplished primarilyby movement of the brush over the surface to be cleaned or polished.Such movement of the brush is in proportion to the circumferential speedof the brush and, consequently, portions of the brush farther from theaxis of rotation of the motor 6 move faster than portions closer to suchaxis. It is principally to attain higher speed of the brush 2 relativeto the floor that the brush is of annular shape rather than being acomplete disk.

In addition to the speed of a brush section relative to a surface to bepolished or scrubbed, the pressure of the brush on the floor is animportant factor influencing the effectiveness of the polishing orscrubbing action. The pressure exerted on the floor by any selectedsection of the brush is determined by the Weight of the machine and thetotal area of the brush 2 over which that weight is distributed. Thereis, of course, a practical limit to the weight of the machine if it isto be capable of being carried manually with reasonable effort. If thebrush 2 is made sufficiently small to exert a high unit area pressure,the surface of the floor being operated on could become undesirablysmall. For general purposes, therefore, a more effective polishing andscrubbing action is obtained by the use of an annular brush having ahollow central portion, which is conventional. Not only is the effectivespeed of movement of such a brush over the floor higher for a givenspeed of rotation of the motor 6, but the actual difference in speedbetween inner and outer portions of the brush is less. It would not bepractical to set the speed of brush rotation to obtain an adequatelinear speed for the center of a disk-type brush because the linearspeed of the peripheral portions of the brush would then he greater thandesirable.

While it is desirable to provide a reasonably great area of contactbetween the brush face and the floor for general polishing and scrubbingoperations, it is desirable under some conditions to be able to apply aconcentrated cleaning or polishing action on a local portion of thefloor surface. Such concentrated scrubbing or polishing action would beadvantageous where there is a black mark on a hardwood floor, forexample, or a stain spot on a carpet. A conventional floor polishing orscrubbing machine cannot be utilized effectively to exert a concentratedpolishing or scrubbing action on such local blemishes. It is not verypractical to provide a special machine for this purpose because in mostcases it would be necessary for an operator to use first one machine andthen another in polishing or scrubbing a particular floor.

As has been mentioned above, the two principal factors in governing theeffectiveness of a polishing or scrubbing operation are the linear speedof movement of the polishing element and the pressure of such element.Also, it is possible to vary at least the scrubbing effectiveness of anelement by varying the material used for it. Thus, if the element ismade of more abrasive material, it will have an increased scrubbingeffect. By utilization of the present invention concentrated pressurefor increased localized polishing or scrubbing action can be obtainedvoluntarily for any desired period by providing a modification for thefloor polishing and scrubbing machine, and, in producing suchconcentrated local scrubbing, the pressure can be increased, or thespeed of movement of the 'scrubbing element can also be increased, anddifferent types of scrubbing elements can be utilized at will.

In FIGS. 2 and 3, a local surface-contacting scrubbing element 11 isshown received in the hollow center of the conventional annular brush 2.In this instance such surface contacting element is a pad of steel wool.Backing this pressure pad is a flexible diaphragm 12 mounted in andclosing the hollow center of the annular brush 2. To facilitatedeflection of such diaphragm, the marginal portion preferably is ofrelatively thin material and the central portion is of relatively thickmaterial so as to be able to withstand pressure and wear more readily.Such diaphragm can be made of any suitable flexible material such assoft rubber or plastic. The marginal portion of this diaphragm issecured firmly to the inner periphery of the brush 2 so that thediaphragm will be turned as the brush rotates.

The diaphragm 12 is made of material sufficiently limp so that by itselfit will not apply any appreciable pressure to the surface-contacting pad11. Also, in relaxed condition the diaphragm will not effect positiverotation of the polishing or abrading pad 11 because it is preferredthat such pad not be secured to the diaphragm in any way, but that itsimply be placed loosely in the central hollow of the annular brush 2.

If pressure is applied to the upper side of the diaphragm 12, itscentral portion will be deflected downwardly to press firmly against theabrasive pressure pad 11 so that its pressure against the floor surfacewill be increased and the rotation of the diaphragm 12 will betransmitted to such pressure pad. Means for thus deflecting thediaphragm downward includes the pressure head or disk 13 located abovethe central portion of the diaphragm, which preferably has a convexlower side and is rotatively mounted on the lower end of pressure rod 14extending upward through the hollow drive shaft 15 of the motor 6. Suchdrive shaft is mounted for rotation relative to the machine casing by anupper antifriction bearing 16 and a lower antifriction bearing 17. Theupper end of the space between the pressure rod 14 and the hollow motordrive shaft 15 is sealed by the upper seal 16' and the lower end by seal17'.

When the floor polishing and scrubbing machine is being used normally,either the concentrated pressure pad 11 can be removed from the brushhollow or downward pressure from the diaphragm 12 can simply be relievedby maintaining the pressure head 13 in the raised position of FIG. 2.The pressure rod 14 will therefore normally be held in raised position,so as to hold the pressure head up, by a compression spring 18encircling the upper end of the pressure rod, bearing on the upper endof the motor casing and pressing upward on spring seat 19 which isattached to the upper portion of the pressure rod. From this positionthe pressure rod 14 and head 13 can be moved downward into the depressedposition of FIG. 3 by the application of downward pressure to the springseat 19. Such downward pressure can be exerted at will and to the degreedesired by swinging of a bell crank including a generally horizontal arm20 and an upright arm 21. Such bell crank is suitably mounted by a pivot22 which is supported from the upper end of the motor by an upwardlyextending bracket 23 shown best in FIGS. 3 and 4.

The horizontal arm 20 of the bell crank has a slot in its outer end toform bifurcations 24 which straddle the upper reduced end portion 25 ofthe pressure rod forming a stem. The slot between these bifurcations isnarrower than the width of the head 26 on the upper end of such stem.The bell crank can be swung in a clockwise direction, as seen in FIGS. 2and 3, from the position of FIG. 2 to that of FIG. 3 to depress thepressure rod 14 by pulling on Bowden wire 27 attached to the upright arm21 of the bell crank by the anchoring bolt 28.

The Bowden wire 27 extends upward generally alongside the handle shank 8through a substantially rigid sheath 29, the lower end of which issupported from the motor by a bracket 30 which is attached to the sheathby an anchoring clamp 31. The upper end of the Bowden wire is secured toan operating lever 32 at a location spaced from the lever-supportingpivot 33 about which such lever swings. The Bowden wire is normally heldin its lowermost position by a compression spring 34 which encircles thelower end of the Bowden wire and reacts between the lower end of thesheath 29 and the point of attachment of the Bowden wire to the uprightarm 21 of the bell crank.

When the Bowden wire is pulled by swinging of the lever 32 toward itsadjacent handle grip 9, the bell crank will be swung so that thehorizontal arm is swung downward into the position of FIG. 3, to depressthe pressure rod. Such rod movement will press the pressure head 13against the upper side of diaphragm 12 to bow it downward as shown inFIG. 3 for exerting pressure on the abrasive pad 11. Such pad will becompressed to make it more firm and, at the same time, greater pressurewill be exerted by the pressure pad on the floor surface. In addition,the pressure of the diaphragm on the pad will be sufiicient so that, asthe rotary brush is turned and the diaphragm 12 is turned with it, thepressure pad 11 will be rotated also.

The rotation of the pressure pad 11 thus effected will be helpful inremoving a spot on a floor but the most important consideration is theconcentration of pressure which can be exerted on the small area of thepad and consequently by the pad on a corresponding small area of thefloor. Such pressure concentration can be effected by applying theweight of the entire polishing and scrubbing machine to the small areacovered by the pad 11 instead of to the much larger area on which thebrush 2 would bear. It will be noted in FIG. 3 that the pressure rod 14has been moved down far enough relative to the motor shaft 15 so thatsuch shaft, the motor, the casing and the brush 2 supported from theshaft will be elevated sufficiently to enable the floor-engaging surfaceof the brush to clear the floor.

Because the pressure head 13 is pressed into intimate engagement withthe diaphgram 12 of rubber, such head will be rotated in synchronismwith the diaphragm. It is preferred, however, that the pressure rod 14not rotate. Consequently, it is desirable to provide a thrust bearingbetween the pressure rod 14 and the pressure head 13 which is shown inthe form of a washer or pressure head thrust bearing disk 35 engagedbetween the upper side of the pressure head 13 and the lower end of thepressure rod 14.

In operation the floor polishing and scrubbing machine can bemanipulated in the usual manner by the operator grasping the hand grips9 on the end of the handle shank 8. At such time as he should notice ablack spot on the floor or a stain on the carpet or some other blemish,he can move the machine so that it is centered over such blemish andthen pull the lever 32 to the desired extent to shift such porportion ofthe m-achines Weight as the operator might wish from being supported bythe floorengaging surface of the brush 2 onto the pressure pad 11.

Instead of the operator being required to manipulate the lever 32selectively to obtain the desired pressure of the pad 11 on the floor,reciprocating mechanism can be provided for the pressure rod 14 whichwill enable the desired pressure application to be achieved in everyinstance simply by the operator pulling the lever 32 into full contactwith the handle grip 9. For this operation mechanism is provided toadjust the length of the downward stroke of pressure rod 14 bymanipulation of the control lever, taking into consideration thethickness of the pad 11.

The modified type of mechanism shown in FIG. 5 enables the throw of thebell crank to be altered for a given movement of the control rod 27' andthe relative positions of the bifurcated bell crank arm 25 and theactuating lever 32 to be selected. With the actuating lever pressedagainst its adjacent handle grip 9 the pin 28' can be inserted throuhg adesired hole 36 in the upright bell crank arm 21 and a desired hole 37in the end portion of the control rod 27 to effect such adjustments.

When the actuating lever 32 is held against the adjacent handle grip 9the upright bell crank arm 21' can be swung to bring a hole 36 in suchbell crank arm into registry with a hole 37 in the end portion of thecontrol rod such that the push rod 14 will be depressed to the lowestposition desired by downward swinging of the bell crank bifurcations 24.The pin 28' can then be inserted through such registering holes 36 and37 and the lever 32 can be released. Whenever the lever 32 is swungagain into engagement with the handle grip 9, therefore, the pressurehead 13 of the pressure means will be depressed into such tmaximumpressure position. Upon release of the lever the compression spring 18will swing the b1- furcations upwardly again by pressure of the springseat 19 on them at the same time that the spring raises the pressure rod14 into its inoperative position.

By use of the apparatus shown in FIGS. 1 to 5 inclusive wax or detergentcan be applied to a portion of the floor alongside the brush 2. As thebrush is moved toward such wax or detergent, the action of the brush isto push the wax or detergent along ahead of the brush. Wax or detergentcan be applied directly to the pad 11 when such pad is to be used forscouring or scrubbing a floor blemish. The pad may also be used as a waxapplicator when it is desired to apply an exceptionally heavy coat ofwax to a spot or small area as, for example, in areas subjected to heavytrafiic, such as doorways. In such instance, the pressure rod can belowered momentarily to apply a daub of wax on the floor and thenretracted without performing any substantial polishing or scrubbingaction.

In FIG. 7 an expedient for delivering liquid wax or detergent throughthe hollow motor drive shaft 15 is shown. In this instance the pressurerod 14' has a central duct 38 extending longitudinally through it. T othe lower end of the pressure rod is attached a nozzle 39 which is incommunication with the duct 38. This nozzle is in registry with anaperture 40 in the central portion of the diaphragm 12. A hose 41 isconnected by a coupling 42 to the upper end of the pressure rod 14' forcommunication with its duct 38.

As shown in FIG. 6 the hose 41 is connected to a reservoir 43 forcontaining the liquid wax or detergent. A charge of such wax ordetergent can be dispensed through hose 41, duct 38 and nozzle 39 byproper manipulation of the plunger or other control 44. A charge ofliquid projected by the nozzle 39 through the diaphragm aperture 40 willbe deposited on the floor within the hollow of the annular brush 2 sothat it will be trapped as the machine is moved in one direction oranother. The liquid in the hollow portion of the brush is engaged by theinner periphery of the brush and rubbed on the floor. None of the liquiddeposited in such brush hollow can escape as long as the brush is incontact with the floor except for such liquid as the inner periphery ofthe brush engages and distributes as the machine is moved across thefloor.

No auxiliary pressure pad 11 is shown in FIG. 7 and it will beunderstood that a liquid-dispensing attachment for the floor polishingand scrubbing machine is not dependent on the provision of a pressurerod 14 except for the purpose of conveying the liquid from the hose 41through the hollow or bore of the motor drive shaft 15. The nozzle 39might simply be connected directly to the lower end of such hollow driveshaft and the pressure head 13 and diaphragm 12 could be omitted. Inthat case, of course, the bell crank 20, 2'1 and its actuating mechanismalso could be omitted.

Where the liquid-dispensing mechanism is provided in addition to thepressure rod 14, pressure head 13 and diaphragm 12, an abrasive pad canbe used beneath the diaphragm 12 or omitted at will. If an abrasive orscouring pad is used with this type of apparatus, it is preferred thatit be of reasonable porous material such as steel woolfWhen this type ofpad is used the liquid wax or 8 detergent can be supplied to it throughthe hose 41 and bore 38 of the pressure rod 14' and dispensed by thenozzle 39 onto the upper side of such pad. The liquid will then passthrough such pad, particularly when compressed by pressure by thediaphragm 12 on it, so as to be applied to the floor from the lower sideof the pad. In such case the operation of the Bowden wire 27, bell crank20, 21, pressure rod 14' and pressure head 13 for pressing the diaphragm12 against the pressure pad will be the same as described in connectionwith FIGS. 2 and 3 in particular.

As has been discussed above, the elfectiveness of a scrubbing actiondepends not only on the type of abrasive material used and theconcentration of pressure by it onto the floor, but also on the speed ofmovement of the floorcontacting surface relative to the floor. If thescrubbing pad 11 is located within the hollow brush 2 and simply isdriven at the same rotative speed as the brush, as will be the case withthe apparatus shown in FIGS. 2 and 3, the actual translational speed ofthe pad 11 relative to the floor will not be very high. Such relativespeed can be increased greatly and virtually to any extent desired byeffecting rotation of the pad 11 independently of rotation of the brush2 and at a considerably higher speed. Mechanism to effect such anoperation is shown in FIGS. 8 and 9.

In this instance the pressure rod 14" has an auxiliary motor 45 attachedto its head 26 on the upper end of such pressure rod. This motor issupported by the pressure rod but is held in position above the pressurerod by parallel uprights 46 extending upward from the main drive motor 6and spaced apart a distance slightly greater than the width of themotor. Slots 47 in the upper portions of these uprights receivetrunnions 48 projecting from opposite sides of the auxiliary motor. Thelengths of slots 47 extend vertically so that such slots guide the motorfor upward and downward movement with lengthwise movement of thepressure rod 14 and the trunnions enable the motor to swing as may benecessary to maintain alignment of the motor axis with the axis of thepressure rod.

In this machine there is no diaphragm extending across the hollow of thebrush 2, but instead, the pressure head 13' mounted on the lower end ofthe pressure rod 14" is engageable directly with the upper side of thepressure pad 11. It is desirable for the lower side of such pressurehead to be covered with friction material, such as rubber, so that whenit is pressed against the pressure pad it will cause such pad to rotatein synchronism with the pressure head. The pressure rod 14" is connecteddirectly to the auxiliary motor 45 so that the pressure head 13' can berotated at a rotative speed considerably greater than the rotative speedof the brush 2 and its driving head 5.

To control energization of the auxiliary motor 45 a control switch 49can be mounted on the actuating lever 32 for depressing the pressure rod14" in the manner described in connection with FIGS. 2 and 3.Alternatively, a switch 49 can be mounted on one of the uprights 46 asshown in FIG. 9 for engagement by a trunnion 48 to effect energizationof the motor automatically when the pressure rod 14" has been depressedto a predetermined degree suflicient to press the abrasive pad 11 firmlyagainst the floor by manipulation of the actuating lever 32 to swingbell crank 20, 21 for depressing the pressure rod.

FIGS. 10, ll, 12 and 13 show somewhat diagrammatically the applicationof an arrangement for applying localized pressure to different types ofconventional floor polishing and scrubbing machines. In the machine ofFIG. 10, the motor 6 again is located centrally over the casing 1 but,instead of the brush being driven through reduction gearing 7 of theplanetary type as shown in FIG. 2, the reduction gearing 7a is of thecompound series type. While in this instance the base of the brush 2 isshown as being integral with one gear of the gearing, the brush could besecured to the gearing by a disengageable coupling if desired.

The pressure head 13a is depressible relative to the brush backing bymechanism operating through a bore coaxial with the brush backing. Thesheath 50 of a Bowden wire actuator has its upper end extending throughand secured in the top of the casing 1. The sheath then extendsdownwardly next toward the center of the machine and finally downwardthrough the bore in the gearing and the brush back to the pressure head.The lower end of the Bowden wire 51 extending through the sheath has ahead received in a cavity provided in a boss in the back of the pressurehead so that downward movement of the Bowden wire through the sheath 50would force the pressure head 13a downward to exert pressure on apolishing or abrading pad 11 beneath it.

Lengthwise movement of the Bowden Wire through the sheath is effected byreciprocating the control rod 27a which is connected to one end of thelever 52 journaled on a pedestal 52' on the casing 1. The other end ofthis lever is secured to the Bowden wire 51. When the control rod 27a ispulled upwardly in the direction indicated by the broken arrow, theBowden wire will be pushed downward to depress the pressure head 13a.The force of such downward pressure will react through the leverpedestal 52' to raise the casing 1 sufliciently to relieve most of thepressure from the brush 2. When the control rod 27a is pushed downwardagain the Bowden wire 51 will be pulled up so that the weight of themachine will be transferred from the pressure head 13a back to the brush2. Upward movement of the Bowden wire will not actually lift thepressure head but it will be raised by the pressure of the floor on thepressure pad 11.

The pressure head 13a is connected to the back of the brush 2 forrotation with it although the pressure head can move up and downrelative to the brush as described above. The pressure head and brushback can be connected for conjoint rotation by a pin 53 projectingupwardly from the pressure head eccentrically of its axis into adownwardly opening socket 54 provided in the brush back. Because thepressure head is thus connected for rotation with the brush back, it isnecessary for the connection between the pressure head and the Bowdenwire to afford relative rotation between these two elements. For thispurpose, the head on the Bowden wire is received loosely in the socketof the pressure head stem receiving the Bowden wire head.

In FIG. 11, the motor 6 is offset from the center of the casing 1 anddrives the brush 2 through reduction gearing 7b including a small andexternal gear driven by the motor 6 which meshes with a large internalgear concentric with and connected directly to the brush. In thisconstruction the pressure head 13a is connected to the lower end of theoffset thrust tube 50'. The upper end of this tube extend slidablythrough an opening in the casing 1 and a head on the lower end of thistube is loosely engaged in a socket on the upper side of the pressurehead, so that such head can rotate relative to the lower end of the tube50'.

The upper end of the thrust tube is pivotably connected to one end of alever 52 which is, in turn, pivotably mounted on the upper end of apedestal 52' projecting upward from the top of the casing 1. Theopposite end of this lever is pivotably connected to a control rod 27a.Normally the thrust tube is urged upward by a compression spring 50engaged between the top of the casing 1 and the lever end. By thisspring acting on the thrust tube, the pressure head 13a is lifted to itsuppermost position shown in FIG. 11. Such pressure head is rotativelyconnected to the brush back by the pin 53 engaged in socket 54 in thebrush back as described in connection with FIG. 10.

The construction shown in FIG. 11 is not only capable of causing thepressure head 13a to exert extra localized pressure when desired, but asmentioned above, the thrust member 50' is a tube. A liquid supply tube51' is connected to the upper end of the tube 50 for the purpose ofsupplying liquid wax or detergent to a hole through the center of thepressure head 13a. Such liquid will be supplied to the tube 51' from asuitable reservoir such as shown in FIG. 6, for example, and the supplyof liquid can be controlled as discussed in connection with that figure.If there is no pad 11 beneath the pressure head, the liquid will bedispensed directly onto the floor. Otherwise, such liquid will bedispensed onto the upper side of the pad and will soak through it.

FIG. 12 shows a drive motor and brush arrangement like that of FIG. 11,but in this instance the pressure head 13a is depressed by a pressurerod 14 similar to that of the apparatus shown in FIG. 1 instead of beingdepressed by a thrust tube as shown in FIG. 11. Such pressure rodextends upward into the cylinder 55 of a fluid pressure jack. Fluidunder pressure, which preferably is hydraulic liquid but may be air, issupplied to such cylinder through a pressure fluid supply line andcontrol valve 56. From such control valve, ducts extend to opposite endsof the jack cylinder so that fluid under pressure can be suppliedthrough one duct and fluid can be returned through the other duct to areservoir to make the jack double-acting. Such jack includes a piston 57received in the cylinder of the jack and mounted on the end of thepressure rod 14 which extends into the jack.

The lower end of the pressure rod 14 is connected to a boss on the upperside of the pressure head 13a in the same manner as that described inconnection with FIG. 11 so that the pressure rod and pressure head canrotate relatively. Also, the pressure head is rotatively integrated withthe back of the brush 2 by a pin 53 carried by the head being engaged ina socket 54 of the brush back as previously described. As in FIG. 11,the connection between the pressure rod 14 and the pressure head 13a isof the type which will enable the pressure head to be lifted by upwardmovement of the pressure rod.

Normally the control valve 56 will be set so that fluid under pressureis supplied to the lower end of the jack cylinder 55 for lifting thepiston 57, the pressure rod 14 and the pressure head 13a as shown inFIG. 12. When it is desired to exert concentrated pressure on aparticular spot, valve 56 is actuated to reverse the supply of fluidunder pressure to the jack 55 so that such fluid will be supplied to theupper end of the jack cylinder for forcing the jack piston and pressurerod 14 downwardly. The pressure thus exerted will be yielding, but theprojection of the pressure rod 14 from the jack cylinder 55 will tend tolift the casing 1 by reaction from the floor through the pressure head13a and pressure rod 14. Because of this action, the pressure of brush 2on the floor will be reduced or it may be possible to lift the brushentirely free of the floor by such an operation.

In the machine shown in FIG. 13, the motor 6 for driving the brush 2 isarranged with the axis of its rotor horizontal whereas the axis ofrotation of the brush 2 is vertical. The drive to the brush isaccomplished through an external V-belt connecting pulleys on the motorarmature shaft and on a shaft carrying one gear of bevel gearing 7c. Thelatter shaft is carried by the casing 1 parallel to the shaft of themotor armature. The size of the cooperating bevel gears and the sizes ofthe two pulleys can be selected so as to obtain a proper speed reductionfrom the motor to the brush. It is preferred that the motor be mountedon the casing 1 so that the shaft of the motor armature extendsdiarnetrally of the casing.

The pressure head and pressure: rod of this machine are similar to thoseof the machine shown in FIG. 12. The difference in structure resides inthe mechanism provided for raising and lowering the pressure rod for thepurpose of raising and lowering the pressure head 113a. In thisinstance, the pressure rod extends upward through a lower edgewise cam58a which is secured on the pressure rod. The upper side of this cam isinclined. The upper 1 1 end of the pressure rod extends from such loweredgewise cam upward into a downwardly opening bore in an upper edgewisecam 58b which has a lower inclined sulface adapted to cooperate with theupper inclined surface of the lower edgewise cam.

Relative rotation of the two cams is effected by attaching the lower endof a Bowden wire 27 extending through sheath 29 to a crank projection58c extending outward from the lower edgewise cam. The upper end of suchBowden wire will be connected to an operating lever 32 mounted on thehandle for the machine as shown in FIG. 1. As the handle is pulled, theBowden wire will rotate the lower edgewise cam 58a and pressure rod 14toward the position shown in FIG. 13 so that interengagement of theinclined cam surfaces will force the pressure rod and the pressure headdownward. The resulting upward pressure on the pressure rod 14 reactingfrom the floor will produce an upward thrust on the upper edgewise cam58b so as to lift the machine and the brush 2 upward for supporting theweight of the machine on the pressure head 13a and pad 11 to provideconcentrated pressure. When the handle is released or the Bowden wire 27is pushed downward, cam 58a will be turned in the opposite directionrelative to cam 58b so that the machine can settle down again onto thebrush 2. This actuating mechanism for the pressure rod 14 enablespositive downward thrust to be exerted on it but does not includemechanism to effect a positive upward force on such rod.

The machine of FIG. 14 has the same type of motor and casing arrangementas shown in FIG. 2 in which the brush attaching coupling 4 is connectedto the reduction gearing 7. The structure of the brush unit itself,however, differs in that the pressure head portion 13b is integral withthe central portion of the brush. The radially outer portion of thebrush back is annular and is arranged to slide up and down relative tothe central portion of the brush back. Grooves 59a on the innerperiphery of the annular brush portion interfit with one or more splines59b projecting outward from the central portion of the brush for thepurpose of rotatively connecting the inner and outer brush backportions. Downward movement of the outer brush portion relative to theinner brush portion is limited by one or more latches 590 in the form oflegs pivotably mounted on the bottom of the central brush portion andwhich can swing outward beneath the outer brush portion.

The outer portion of the brush back carrying the brush 2 can be held inits lower position by one or more pressure feet 6011. If more than oneof such pressure feet is provided, they will be distributedcircumferentially around the casing 1. Each pressure foot is mounted onthe lower end of a pressure spindle 60b which is slidable up and downthrough an aperture in casing 1 and a collar 60c mounted on andprojecting upward from such casing encircling the spindle-receivingaperture. The spindle can be pressed downward relative to such collarand aperture by exerting pressure on the head 60d on the upper end ofthe spindle and the spindle can be held in a depressed position by alatch pin 60a slidable through the side of collar 600 into a socket holeor groove in the side of the spindle. The latch pin can be pressedinwardly to maintain such holding engagement with the spindle by aspring 60 When the floor polishing and scrubbing machine is being usednormally, the pressure spindle or spindles 60b will be held in theirlowered positions to keep the outer portion of brush 2 depressedrelative to the inner portion of such brush. The weight of the polishingmachine will therefore be carried principally by the outer portion ofthe brush by such weight being transmitted to such brush portion throughthe pressure spindle or spindles and pressure foot or pressure feet. Thepressure foot 60a or the upper side of the brush back or both are madeof low friction material to minimize friction between the pressure footor feet and the brush back as the brush is rotated relative to 12 thecasing 1. Alternatively the pressure foot could be replaced by a roller.

When it is desired to apply concentrated pressure to a particular spoton the floor, the latch pin e is pulled outward in opposition to spring60 until its inner end is withdrawn from the socket in the spindle 60b.The weight of the machine will then be transferred from the pressurespindle or spindles to the pressure head 13b and the pad 11' of cleaningor polishing material beneath it. When the particular spot has beenscrubbed or polished sufficiently, the pressure spindle or spindles 60bwill be pushed down again and latched so as to transfer the weight ofthe machine back to the annular brush 2. If desired, a disk of abradingmaterial 2 such as sandpaper can be placed beneath both the brush 2 andthe pressure pad 11 for sanding a floor.

The machine of FIGS. 15 and 19 also is generally like that of FIGS. 1and 2. The brush 2 is received in the recess 3 of the casing 1, and suchcasing carries the motor 6 which rotates the brush 2 through reductiongearing 7. The brush is mounted by the brush-attaching coupling 4 on thedriving head 5. The principal difference between the apparatus shown inFIGS. 15 to 19 and the various types of concentrated pressure apparatusdescribed above is that, in this instance, the concentrated pressureapparatus and its control mechanism are carried principally by the brushso that such mechanism can be added more readily to a floor polishingand scrubbing machine as an accessory.

In this instance, the pressure head 13c is larger than the pressure head13 of FIGS. 1 and 2. Themechanism for moving such pressure head downwardrelative to the annular brush 2 includes a braking rod 61 extendingthrough a guide and housing 62 for such rod. A compression spring insuch housing encircling the braking rod reacts between the bottom ofsuch housing and a set collar 63' on the rod to push the rod upward,normally, into the position of FIG. 15. The upper end of such rod isrounded and can seat on an insert 52" of antifriction material such asTeflon carried by the swinging end of a lever 52 of channel shape. Thislever can be swung by reciprocation of a control rod 27a of the typedescribed in connection with FIGS.10 and 11.

A downwardly tapered conical braking roller 64 is mounted on the lowerend of the braking rod 61 for engagement with the beveled periphery of afloating disk 65 which is attached to the pressure head 130 by aplurality of circumferentially spaced posts 66. FIG. 16 shows three ofsuch posts spaced apart The heads of such posts are welded or otherwisesecured to the floating disk 65 and their lowers ends may be fitted intosockets in the margin of the pressure head 13c and secured in place byscrews as shown in FIGS. 15 and 18. The disk 65 is main tained in itscentered position by the guiding cooperation between its centralaperture and the exterior of the hub 68 of brush 2 over which it isfitted. Such hub projects upward from the brush and carries the brushattaching coupling 4 engaged with the driving head '5, which is rotatedby motor 6 through reduction gearing 7.

When the braking roller 64 is out of engagement with the inclined edgeof disk 65, such disk will be maintained in its raised position of FIG.15 by compression springs 67 encircling the respective posts 66 andengaged between the upper side of the brush back and the lower side ofthe disk 65. Also, the disk 65 will be turned in synchronism with thebrush 2 by a large torsion spring 67' encircling the hub 68 and havingone end engaged with such hub and its other end anchored to plate 65, asshown in FIGS. 15 and 18. The disk 65, posts 66 and pressure head can,however, turn through a small angle relative to the brush back in thedirection opposite the rotation of the brush because the posts extendthrough slots 69 elongated circurnferentially of the brush back as shownin FIG. 16.

In FIGS. 15 to 19, pressure head guides are shown which guide therelative elevational movement of the pressure head 13c and the brushback. Each of these guides includes an inclined row of rollers 71mounted in a downwardly opening recess in the brush back which areengaged by the upper inclined surface of a wedge block 72 carried by theupper side of the pressure head 13c. As downward pressure is exerted bythe roller 64 on the margin of the floating disk 65 by downward movementof the rod 61 caused by tilting lever 52 from the position shown in FIG.15 to that of FIG. 18, the wedging action of the wedges 7'2 presses thepressure head 130 downwardly in opposition to the force of compressionsprings 67 so that such pressure head will be moved from the position ofFIG. 15 to that of FIG. 18 while the pins 66 move along the slots 69 inthe direction opposite the direction of rotation of the brush. Suchturning of the disk 65 relative to the brush will be in opposition tothe torsional driving force exerted by torsion spring 67' between thehub 68 and the disk.

When the braking effect of the roller 64 on the rim of disk 65 hascaused such disk to move so that the posts 66 have again come into aposition of equilibrium in the broken-line positions of FIG. 16 with thepressure head 13c depressed to the position of FIG. 18, the roller 64again will be driven at a speed corresponding to the speed of rotationof disk 65 and brush 2 and the upper end of braking rod 61 will sliprelative to its Teflon seat 52". Such slipping action will continue aslong as the braking rod is held in the depressed position of FIG. 18.

When the upward force on control rod 27a is released, the compressionspring 62 will raise the braking rod 61 to withdraw the braking roller64 from engagement with the periphery of disk 65. The springs 67 willpromptly move disk 65 and pressure head 13c upward relative to the brushback to the position of FIG. 15 so that the concentrated pressure is nolonger exerted by the pressure head. Simultaneously, the torsion spring67' will turn the disk 65, pressure head 13c and posts 66 relative tothe brush in the same direction that it rotates until the posts areagain in engagement with the leading ends of the slots 69 as shown inFIG. 16. The brush 62 can then effect its customary scrubbing orpolishing operation.

The pressure head 130 shown in FIGS. 15 and 18 is of circular shapehaving a marginal rib by which a greater pressure would be exerted onthe pressure pad 11' than would be exerted on it by the recessed centralportion of the pressure head. In FIG. 20, a pressure head 13d of adifferent type is shown having ribs radiating from its central portion.It will be understood that pressure heads of various other designs couldbe used if desired.

In the floor polishing and scrubbing machine of FIG. 21 the variouscomponents are similar to those of the machine shown in FIGS. 15 to 19except that, in this instance, an annular type of concentrated pressuremember 1312 has been substituted for the disk type of pressure headshown in FIGS. 15, 18- and 20. Such annular pressure head fits into adownwardly opening annular groove in the back of the brush 2. In thisinstance, the pressure head posts 66' have their lower ends secureddirectly in the upper side of the pressure head ring. In this instance,the actual floor-engaging element can be a disk underlying the brush 2and pressure head ring 132. Such floor-engaging member may be a mat ofsteel wool or a sandpaper disk or a felt pad. Since the mechanismutilized for raising and lowering the pressure head is the same as thatdescribed in connection with FIGS. 15 to 19, such descrip tion need notbe repeated. In this instance, however, the wedge blocks 72 can beformed as integral parts of the ring 13c.

In the floor scrubbing and polishing machine of FIGS. 22 to 25 themember previously designated as a brush 2 is replaced by a back 2 havinga flat annular lower surface bearing on a polishing or abrading pad 2which is the equivalent of a scrubbing or polishing brush. Thebackattaching coupling 4 secures the brush back 2 to the driving head 5which is rotated by the motor '6 through the speed-reducing gearing 7.In this instance the pressure head for exerting concentrated pressure iscarried by or forms a component of the removable brush back 2. Whilesuch pressure head could be simply a ring comparable to the ring 13e ofthe structure shown in FIG. 21, it is preferred that the pressure headring 13 shown best in FIGS. 23 and 24 carry on its underside somewhatresilient projections 13g which are spaced circumferentially of the ring13 The aggregate area of the projections 13g contacting the floorengaging pad 2' is considerably less than the total area of the ring137". When this ring is depressed so that the projections 13g are belowthe general lower surface of the back 2, such pressure head componentswill cause the corresponding small portions of the pad 2' to bearprimarily on the floor.

In this instance also, depression of the annular pressure head 13 13g iseffected by braking mechanism. Moreover, the brake-actuating mechanismused in this machine is similar to that described in connection withFIGS. 15 and 18. Thus, the brake-actuating mechanism includes thevertically reciprocable rod 61 extending through the housing and guide62. Such rod is normally held in the upper position by the compressionspring 63 received in the housing and engaged between the bottom of thehousing and the set collar 63' on the braking rod. Such rod is depressedby swinging lever 52 mounted on pedestal 52, one end of which lever isengaged with the upper end of rod 61 and the other end of which isconnected to control rod 27a. A braking pressure foot 64 is carried bythe lower end of rod 61.

Spaced flanges 73 project upward from the annular pressure head 13 atopposite ends of the projections 13g. These flanges fit slidably withincavities 74 spaced circumferentially of the brush back 2 as shown inFIGS. 23 and 24. A control ring 75 overlies the several cavities and isconnected to the concentrated pressure head ring 13 by means to effectdepression of such ring.

The thrust mechanism interconnecting the pressure head ring 13 and thecontrol ring 75, which is shown in FIGS. 22 to 26 inclusive, includes athrust loop 76 having its lower end pivoted in an anchor block 77carried by the pressure head ring 13] and its upper end pivoted in theanchor block 78 carried by the control ring 75. While the flanges 73 onthe pressure head ring 13) engaged in the cavities 74 of the brush back2 prevent such ring 13 from shifting circumferentially relative to thebrush back, the control ring 75 can shift circumferentially relative tothe brush back, but only to the extent permitted by the thrust loop 76which connects the two rings.

As the ring 75 moves circumferentially relative to the back 2 and thepressure head 13 from the position shown in FIG. 23 to that of FIG. 24,the angle of the thrust link changes relative to the two rings so as toforce them apart. Normally, these rings are held in their relationshipof closest approach to each other shown in FIG. 23 by strong tensionsprings 79 extending respectively through the thrust loops 76. Anchoringloops on the opposite ends of such springs are engaged respectively inapertures of lugs 81 on the upper side of pressure head ring 13 and lugson the lower side of control ring 75. As the control ring is movedcircumferentially or" the brush back 2 from the position of FIG. 23toward the position of FIG. 24, the change in angular relationship ofthrust loop 76 to the two rings will force them apart. Such relativemovement of the rings will stretch spring 29 in the manner indicated inFIG. 24 which tends to shift the ring 75 circumferentially back to theposition shown in FIG. 23.

As indicated in FIG. 24, the circumferential movement of ring 75 movesthe thrust loops 76 into positions to force apart the pressure head ring13 and the control ring 75. Backing clips 82 are engaged over theopposite edges of the control ring 75 at the locations of the pressurehead projections 13g as shown in FIGS. 25 and 26. Such backing clipslimit the movement of the control ring upwardly from the brush back 2and consequently the thrust force exerted by the loops 76 moving fromthe position of FIG. 23 toward the position of FIG. 24 effects movementof pressure head ring 13 downward relative to the brush back 2 from theposition of FIG. 23 toward that of FIGS. 24, and 26 to exertconcentrated pressure on corresponding areas of the pad 2'.

As indicated by the arrows in FIGS. 23, 24 and 25, the brush back 2 isturning in the direction opposite that in which the control ring 75 mustmove relative to such back in order to eflect the downward movement ofthe pressure head ring 13 relative to the brush back described above.Such relative movement can be accomplished by applying a braking forceto the control ring so as momentarily to deter movement of such controlring with the rotating brush back 2. Such braking force is applied tothe control ring by reciprocating downward the braking rod 61 to pressthe braking foot 64 on its lower end against the upper side of thecontrol ring 75. Excessive friction between the control ring and thebrush back 2 is avoided by providing two ribs 83 of antifrictionmaterial, such as Teflon, extending along opposite edges of the controlring to bear on the upper side of the brush back 2. The degree ofcircumferential shifting of the control ring 75 relative to the brushback by such application of braking force is limited by the engagementof a stop lug 84 projecting from an edge of such control ring with astop boss 85 projecting upward from the brush back 2 as shown in FIGS.24 and 25.

As shown best in FIG. 23, in the particular form of machine representedby FIGS. 22 to 26 inclusive, the brush element may include a back 2having a facing 2 on its lower surface which may be resilient forengaging the pad 2'. When the pressure head ring 13f, 13g is depressedrelative to the brush back 2, the concentrated pressure head projections13g will first be moved down into engagement with the pad 2' from thepositions shown in FIG. 23 if they are not engaged with the pad andfurther circumferential shifting of control ring 75 relative to thebrush back will then cause the thrust loops 76 to lift the control ringwhich, in turn, will raise the brush back to a position such as shown inFIGS. 25 and 26 by lifting force transmitted through the backing clips82. The braking rod 61 can be held down in its brake-applying positionas long as concentrated pressure of selected portions of pad 2' on thefloor is desired. When the downward pressure on braking rod 61 isrelieved, spring 63 will raise such rod to retract pressure foot 64'from engagement with the control ring whereupon the weight of themachine and the force of springs 79 will shift control ring 75circumferentially in the opposite direction from the position of FIG. 24to the position of FIG. 23. Such shifting of the control ring will tiltthe thrust loops 76 back to the position of FIG. 23 so that the springs79 can raise the pressure head 131, 13g back into the position of FIG.23.

In FIGS. 27, 28 and 29, a somewhat different type of thrust mechanism isshown. In this machine, thrust struts 76 are substituted for the thrustloops 76 of the machine shown in FIGS. 22 to 26 inclusive. The lower endof each thrust strut has a ball 77 engaged in a socket in the upper sideof a pressure head disk 1311. A ball 78 on the upper end of each thruststrut 76' is engaged in a socket in the lower side of the control ring75. Instead of the pressure head 1311 being, or being associated with,an annular ring, such pressure head may be circular as shown in FIG. 29and may be engageable with the upper side of a pressure head in the formof a flexible diaphragm 13i which is made of rubber or other resilientmaterial.

When the braking foot 64' is moved downward from a position such asshown in FIG. 27 into contact with the upper side of the control ring 75as shown in FIG. 28, the resulting circumferential shift of the controlring will alter the angle of the thrust strut 76' such as from thatshown in FIG. 27 to that of FIG. 28. Since the control ring is held byclips 82 from moving upward away from the brush back, the struts willforce the pressure head 13h downward against the flexible pressure head13i which in turn will be pressed against corresponding locations of thepad 2. The pressure head disks 13h will be guided for movement downbelow the bottom the brush back 2 by posts 86 spaced diametrally of thepressure head disk and slidably received in bores of the brush back asindicated in broken lines in FIGS. 27 and 28. When the brake foot 64' israised from engagement with the control ring, the weight of the machineexerted on the thrust struts 76 and the resilience of the pressure headmembers 13i will shift control ring 75 circumferentially relative to thebrush 2 in the direction in which such brush is rotating and willretract the pressure head disks 13h from the position shown in FIG. 28to that of FIG. 27 until the braking foot again is engaged with thecontrol ring 75 to effect the next concentrated pressure operation ofthe machine.

FIGS. 30, 31 and 32 show a floor scrubbing and polishing machine inwhich the concentrated pressure head is formed by a tube 13j mounted onthe bottom of the brush backing which is inflatable and therebyexpandable from the flattened condition shown in full lines in FIGS. 30,31 and 32 into the broken-line condition of FIG. 31 in which the tubepresses against a localized area of the scrubbing or polishing pad 2beneath it. Air under pressure is supplied to the tube through a conduit87 to inflate it. One end of such conduit is connected to the tube andthe other end is connected to an air pressure controlling cylinder 88.Compressed air is supplied to such cylinder from a tank or reservoir 89provided in the brush back 2 under the control of an air supply controlmember including a stem and a piston 91 carried by the stem, received inthe cylinder 88 and sealed relative to such cylidner by sea1 ing rings92 which are spaced axially of the piston.

A port 93 through the wall which is common to the compressed air tank 89and the cylinder 88 is located between the two sealing rings 92 when thepiston 91 is in its uppermost position of FIG. 31. A piston port 94through the piston head establishes communication between the portion ofthe cylinder 88 above the piston and the portion of the cylinder belowthe piston at all times. Normally, a compression spring in the cylinderholds the piston '91 up in its uppermost position so that port 93 willbe located between the sealing rings 92 which will prevent air passingfrom the reservoir 89 through the port 93 either into the portion ofcylinder 88 above the upper ring 92 or below the lower ring 92. The stem90 is hollow and it has a bleed opening 96 through its upper end forexhausting air under pressure from the cylinder to the atmosphere.

If the air supply controller stem 90 and piston 91 are moved downwarduntil the upper sealing ring 92 of the piston is below the port 93, airunder pressure can flow from the compressed air supply tank 89reasonably freely through the port 93 to the upper portion of thecylinder 88 and through the piston port 94 to the lower portion of thecylinder 88 and the conduit 87 for inflating the concentrated pressurehead tube 13j. Air Will leak from the cyl linder to the atmospherethrough the hollow stem 90 and bleed opening 96 but the ports 93 and 94are so much larger than such bleed opening that the concentratedpressure tube 13 will remain inflated as long as the upper sealing ring92 of the pressure control piston is below the air supply port 93. Whenspring 95 moves piston 91 upward to its uppermost position of FIG. 31,the supply of air under pressure to cylinder 88 through ports 93 and 94will be cut off and air will gradually bleed from the cylinder, conduit87 and tube 13 through the bleed port 96 to the atmosphere so that thepressure head tube will deflate.

In order to move stem 90 down into position for elfecting a supply ofair under pressure from the reservoir 89 through ports 93 and 94 toconduit 87, a tiltable plate 97 is mounted on the rotatable brush 2 forrotation with it. Normally, such plate is held in a horizontal positionparalllel to the brush back by a compression spring 98 interposedbetween the upper side of the brush back and the lower side of the plate97 and encircling a telescoping guide rod 99. The upper side of controlplate '97 bears against the underside of head 100 on the upper end ofsuch telescoping guide rod. The periphery of control plate 97 can bedepressed at one location by a roller 101 movable downward intoengagement with the periphery of the control plate but which roller isnot shiftable circumferentially of the plate. Such roller can be moveddownward by mechanism such as illustrated for controlling theelevational position of the braking roller 65 in FIGS. and 18 or thebraking foot 64' in FIG. 22.

When the control wheel 101 is depressed from the solid line position ofFIG. 31 to the broken-line position of that figure, the wheel willengage the upper surface of the control plate 97 at one location andtilt it into the brokenline position illustrated in opposition to theforce produced by spring 98. The bottom of such tilted plate will engagethe upper end of the control member spindle 90 and move it downwardsufliciently so that the upper sealing ring 92 of piston 91 will beshifted below the air supply port 93. As the brush 2 and control plate97 rotate away from the location of the wheel 101, however, the portionof the control plate above the stem 90 will rise and spring 94 will movethe control piston upward correspondingly, until it has again reachedthe position shown in full lines in FIG. 31 in which the port 93 will beeffectively closed. The portion of control plate 97 above stem 90 willcontinue to move upward until it reaches a position diametrally oppositewheel 101 and thereafter as such portion of the plate continues torotate toward wheel 101, such portion will be moved downward again untilit reaches the brokenlme position shown in FIG. 31 as it again passesbeneath the wheel 101. As the brush 2 rotates, therefore, the controlstem 90 and piston '91 will be alternately depressed and raised tosupply air intermittently to the conduit 87 and tube 13 Because thebleed port 96 is quite small, however, the tube 13f will remain inflatedas long as the wheel 101 is maintained in its lowered position eventhough air under pressure will be supplied only intermittently to thetube 13 through the cylinder 88.

The compressed air supply reservoir 89 carried by the brush 2 could besupplied with compressed air periodically. It is preferred, however, toincorporate an air pump in the machine which will operate automaticallyto pump air into the reservoir at least whenever air is being withdrawnfrom it for inflating the pressure head tube 13 or even more frequently,if desired. Such pump mechanism is shown in FIG. 30. The pump elementincludes a stem 102 carrying a piston 103 which is received in acylinder 104 in the brush back 2. Such piston is sealed relative to thecylinder 104 by sealing piston rings 105. Normally, such piston ismaintained in the upper position shown in FIG. by a compression spring106 engaged between the bottom of the cylinder and the piston 103. Inthe bottom of the cylinder is an air supply port 107 controlled by acheck valve which prevents air from being forced out of the cylinderthrough such port. A port 108 controlled by a check valve establishescommunication between the cylinder 104 and the compressed air reservoir89 but prevents air from flowing from such reservoir to the pumpcylinder. A vent 109 for the reservoir is controlled by a pressurerelief valve so as to limit the maximum pressure which can be built upin the reservoir.

The pump mechanism shown in FIG. 30 is operated by the same controlwheel 101 as is used to effect inflation of the inflatable pressure headtube 13 as described in connection with FIG. 31. It is preferred,however, that the stem 102 of the pump mechanism be longer than the stem90 of the tube-inflating control mechanism so that the pump mechanismwill be actuated by moving wheel 101 downward through a smaller distanceto tilt control plate 97 into the broken-line position shown in FIG. 30.

When the plate is in this position, its lower side would not contact theupper end of the stem if such stern were in radial alignment with thewheel 101. Each time the stem 102 passes the circumferential location ofwheel 101 in its lowered broken-line position of FIG. 30, the pump stem102 will be depressed at least to some extent to force air from cylinder104 through port 108 and past its check valve into the reservoir 89. Asthe plate 97 rises, spring 106 will raise piston 103 so as to draw airthrough port 107 past its check valve into cylinder 104 for replenishingthe air forced by descent of such piston from the cylinder into thereservoir 89. It will be appreciated that the farther wheel 101 is moveddownward, the more control plate 97 will be tilted as the brush 2rotates and consequently the farther downward pump stem 102 will beforced during each revolution. The length of stroke of piston 103 thuseffected will determine the amount of air pumped :from cylinder 104 intocompressed air reservoir 89 during each revolution of the brush.

In addition to exerting concentrated localized pressure for cleaning orpolishing when desired with the machine shown in FIGS. 30, 31 and 32, itis also possible with this machine to dispense detergent or polishingliquid periodically when desired. Mechanism for effecting such a liquiddispensing operation is shown in FIG. 32. A stem 110 carries a piston111 which is received in a cylinder 112. Sealing rings 113 provide aseal between such piston and its cylinder. A compression spring 114engaged between the bottom of cylinder 112 and the piston normallymaintains such piston in the raised position shown in FIG. 32. Liquid isdispensed from the cylinder 112 through an outlet 115 controlled by acheck valve. Liquid is supplied to the cylinder from a tank 116 in thebrush back 2 through a conduit 117 which is controlled by a check valve118.

From a comparison of FIGS. 30, 31 and 32, it will be seen that theconcentrated pressure control stem 90 of FIG. 31 is shorter than thepump-actuating stern 102 of FIG. 30 and that the liquid dispenser stem110 of FIG. 32 is shorter than the concentrated pressure control stem 90of FIG. 31. Consequently, if control wheel 101 is in the full-lineposition shown in all of these figures, the control plate 97 will not betilted at all. If the control wheel is moved downward to the broken-lineposition shown in FIG. 30, the control disk 97 will be tiltedsufficiently so that the pump stern 102 will be reciprocated to someextent. If the control wheel 101 is lowered to the position shown inbroken lines in FIG. 31, both the pump stem 102 and the concentratedpressure stem 90' will be reciprocated as the brush revolves so that,because of its longer stroke, the pump piston 103 will pump more airinto the reservoir 89 and the pressure head tube 13j will be inflated.If the control wheel is lowered still farther to the broken-lineposition of FIG. 32, the control plate 97 will be tilted still more tothe broken-line position of FIG. 32 in which it will engage and depressthe liquid-dispensing stem 110.

The amount of liquid dispensed by reciprocating the stern 110 will bedependent on the degree to which the control plate 97 is tilted. Thedownward reciprocation of the stem 110 once each revolution will causethe piston 111 to discharge a squirt of liquid through the dischargenozzle 115. Between squirts, the upward movement of piston 111 effectedby spring 114- will draw liquid from the tank 116 through conduit 117and past check valve 118 to replenish the supply of liquid in thecylinder. Because stem 110 is shorter than stem 90 of the concentratedpressure controller, dispensing of liquid from tank 116 can beaccomplished only when concentrated pressure is also being applied tothe pad 2 by the inflated pressure tube 13 Also, because theconcentrated pressure controller stem 90 is shorter than the pump stem102 of FIG. 30, the pump will always be operating when the concentratedpressure control is in the pressure-exerting position.

While, as mentioned above, the structure shown in FIGS. 30, 31 and 32will enable liquid to be dispensed only when the concentrated pressuremechanism is actuated, the devices shown in FIGS. 33 to 37 inclusiveenable liquid to be dispensed at will but without having anyconcentrated pressure mechanism. In each instance delivery of liquid iseifected by reciprocation of a rod 61 downward by mechanism similar tothat disclosed in FIGS. 15, 18 and 22. In the device shown in FIG. 33,liquid is dispensed from a tank 119- in the brush back 2 which opensdownward. The open side of such tank is closed by a plate 120 secured inplace by screw threads .121. Such plate can be rotated to apply it or toremove it by engaging lugs of a special wrench in sockets 122 openingdownwardly.

Liquid is discharged from the tank 119 through a hole 123 in the cover120, which hole is sufiiciently small so that the liquid will not dripout of the hole when the pressure in the tank is atmospheric.Alternatively, or in addition, liquid can be dispensed from the tank 119through a passage 124. Pressure can be exerted on the liquid in the tank119 in excess of atmospheric pressure for the purpose of dispensing suchliquid by moving downward a flexible diaphragm 125 forming the top ofthe liquid tank such as to the broken-line position shown in FIG. 33.Such movement can be effected by exerting on the upper side of thediaphragm a pressure greater than atmospheric pressure. For thispurpose, a piston 126 is provided in a cylinder 127. Normally the pistonis held in its upper position by a compression spring 128. The piston ismoved downwarl by downward reciprocation of the piston rod 129 effectedby application of pressure to the head 130 on the upper end of suchpiston rod. Such pressure is exerted by a roller 131 carried by stem 61which rolls over a hinged plate 132 overlying the piston stem head, asshown in FIG. 35.

Air can be admitted from the atmosphere to the cylinder 127 through aduct 133 in the brush back 2 past a check 'valve 134. Downward movementof piston 126 in the cylinler will force air from it through passage 135and past a check valve 136 into the chamber 137 above diaphragm 125. Asthe brush turns, the roller 131 will depress the piston 126 each time itpasses roller 131. Thus the liquid will be dispensed from the tank 119in squirts. An air discharge duct 138 establishes communication betweenchamber 137 and atmosphere through a bleed outlet 139 so that, each timeit is desired to dispense liquid, it will be necessary to build up thepressure in chamber 137 again. Alternatively, the element 139 could be apressure relief valve. A vent passage 140 is also connected to the airdischarge duct 135 so that air can be discharged to the atmospherethrough a bleed outlet 141. Consequently, air under pressure will not bestored in the cylinder 127 for any appreciable period of time but willbe developed by reciprocation of the piston 126 by a few revolutions ofthe brush 2 when it is desired to efiect a liquid-dispensing operation.

In the apparatus of FIG. 34, the air supply mechanism is the same asthat shown in FIGS. 33 and 35. In this instance, however, the liquid tobe dispensed, instead of being stored directly in a tank 119, iscontained in a tube 142 of metal or plastic. The material in such tubecould be of wax consistency if desired. Air under pressure supplied fromduct 135 past valve 136 to chamber 137' will collapse tube 142progressively to force its contents out of the discharge spout 143 intothe duct 124 from which it is dispensed.

The apparatus of FIG. 36 again includes mechanism for producing airunder pressure like that shown in FIGS. 33, 34 and 35. In this instance,however, the tank 144 held in a cavity of the brush back 2 by retainingbands 145 is substituted for the tank'119 formed by the cavity itself asshown in FIG. 33 and for the collapsible tube 142 of FIG. 34. Thecontents of the tank 144 may be pressurized such as by an aerosol toeject a pressure spray 146 when the head 147 is depressed relative tothe tank. Depression of such head can be elfected by a pin 148engageable with it and carried by a plunger 149 reciprocable in thepassage 135. Such plunger has a bleed opening 150 through it andnormally is urged to the left into the solid-line position by acompression spring 151 encircling the pin 14 8 and bearing against theplunger 149.

As the piston rod head and plate 132 pass under the lowered roller 131,air will be drawn into the cylinder 127 through the duct 133 past thecheck valve 134. When the piston is driven downward, air will be forcedout of the cylinder through duct to press plunger 149 to the right sothat pin 148 will be pressed against the head 147 of the aerosol can toeffect a liquid dispensing operation. As soon as reciprocation of thepiston 126 stops, air will bleed from the passage 135 through the ductto relieve the pressure in the passage 135 so that spring 151 can returnthe plunger 149 to the left and withdraw pin 148 so that the aerosoltank dispensing valve can close,

In the machine shown in FIG. 37, the liquid in the tank 152 ispressurized in any suitable manner such as by supplying gas underpressure through the passage 153 controlled by a check valve. Suchpressurized liquid will be pushed into duct 154 but it cannot passthrough the valve passage 155 in plunger 156 as long as the valve isheld in the raised position shown in FIG. 37 by the compression spring157 in the cylinder 158 beneath the valve. When the roller 131 is moveddownward to depress the valve stem 129 intermittently in opposition tothe force of spring 157, liquid will be discharged from the tank 152correspondingly intermittently through the duct 154 and valve passage155 into the discharge duct 159.

The floor polishing and scrubbing machine shown in FIGS. 38 and 39 hasmechanism operable alternatively for exerting concentrated pressure onsmall areas of the pad 2 and for dispensing detergent or polishingliquid. In this instance, however, the concentrated pressure exertingapparatus and the liquid dispensing apparatus cannot be operatedsimultaneously. The concentrated pressure element 13k shown in FIGS. 38and 39 is located near the circumference of the brush back 2. Suchconcentrated pressure element has a skirt 160 slidable in a cylinder 161formed in the brush back. A stem 162 extends upward from the centralportion of the concentrated pressure element 13k and downward movementof such stem will project the concentrated pressure element from theretracted position shown in FIG. 39 downward and outward to the positionshown in FIG. 38 for exerting concentrated pressure on the pad 2'.Downward movement of stem 1 62 is accomplished by tilting annularcontrol plate 163- from the broken-line position to the solid-lineposition shown in FIG. 38.

By tilting one circumferential portion of plate 163 from the position ofFIG. 39 to that of of FIG. 38, the plate presses on the head cap 164 ofstem 162. Local depression of the edge of plate 163 at a particularcircumferential location can be accomplished by lowering control wheel165 which is carried by the lower end of control rod 166. The head 167on such control rod can be engaged by a lug 168 projecting from one endof a rocker 169 pivoted generally centrally. Such rocker can be tiltedby applying a foroce in one direction or the other to arm 170. The head167 of rod 166 is held in engagement with lug 168 by compression spring171 encircling such rod.

As long as the rocker 169 is kept tilted sufficiently to hold wheel 1 65down in the position shown in FIG. 38, the plate 163 will be tilteddownward into the solid-line position at the location of the wheel whichcorresponds once during each revolution to the location of stem 162. Asthe circumferential location of the concentrated pressure unit 13k turnsaway from the location at which wheel 1465 is mounted on casing 1,compression spring 172 enclrcling stem 173 which has been compressed bydownward tilting of plate 163 will expand to move the plateprogressively away from the head 164 of the pressure element stem 162during the next half revolution. Upward movement of the plate will belimited by its contact with the bottom of head 174 of stem 173. However,it is desirable to maintain such pressure head substantially in itsdownwardly projected position in all rotative positions of the brush 2as long as the control wheel 165 is maintained in its lowered position.The pressure head is held in such position by supplying liquid to theinterior of cylinder 161 through conduit 175 from the liquid supply tank152. Such liquid may be polishing or detergent liquid and preferably isunder pressure in such tank.

In the end of conduit 17S adjacent to cylinder 161 is a check valve 176which is normally held closed by spring 177. The check valve element hasgrooves in its circumference so that when it has been moved away fromits seat, liquid will flow freely through the conduit 175 past suchcheck valve into the cylinder 161. As soon as the liquid pressure inconduit 175 and in cylinder 161 are substantially equalized, however,spring 177 will close the check valve. If the pressure in cylinder 161then exceeds the pressure in conduit 175, liquid will bleed back throughthe bleed aperture in the center of the valve 176 until the pressure onopposite sides of the valve has been substantially equalized.

When the brush back 2 has been rotated from the position shown in FIG.3-8 sufiiciently so that spring 172 has raised plate 163 to thebroken-line position, downward pressure will no longer be exerted by theplate on the head 164 of stem 162. During downward movement of pressurehead 13k, however, the volume of cylinder 161 will have increased thusreducing the pressure in the cylinder and causing liquid to flow throughthe conduit 175 from tank 152 to fill the enlarged volume of thecylinder. Downward pressure of the weight of the machine will tend toforce pressure head 13 k upward to reduce the volume of cylinder 161again, but the liquid in such cylinder can escape only slowly throughthe bleed aperture of valve 176 to the conduit 175. Consequently, thepressure head 13k will be retracted only to a slight extent during theportion of the rotation of plate 163 during which the pressure head isout of substantially the radial position of roller 165. When this rolleris raised to the elevated position of FIG. 39, however, the pressure ofthe floor on pressure head 13k will force liquid from the cylinder 161back through the bleed orifice of valve 176 so that the pressure headwill be restored to its retracted position of FIG. 39 within a fewrevolutions after the wheel 165 has been raised.

When the pressure head 13k is in its raised position of FIG. 39,polishing or detergent liquid can be dispensed from cylinder 161 to thepad 2' through a discharge aperture 178 in the bottom of the pressurehead. Discharge of liquid through such aperture normally is prevented bya check valve 179 located in the bottom of the hollow stem 162. Liquidcan be dispensed at will by reciprocation of plunger 180, the upper endof which projects upward through the cap 164 on the upper end of stem162 and through an aperture 181 in plate 163. A small plate or flap 182overlies this aperture and is engageable by a wheel 183 carried by astem 184 having a head 185 on its upper end. This stern can be depressedby engagement with it of lug 186 projecting from the end of rocker 169remote from that carrying lug 168.

When the rocker 169 is rocked oppositely from its position shown in FIG.38, lug 186 will engage the head 185 of stem 184 to press such stemdownward through casing 181 so that wheel 183 will roll on flap 182 andpress it against the upper side of plate 163 if such plate is in theraised position shown in broken lines in FIG. 38 and in solid lines inFIG. 39. When the pressure of lug 186 on head 185 is removed by tiltingthe rocker 169 in the opposite direction, compression spring 187encircling rod 184 and reacting between the casing 1 and the head 185 ofsuch rod will raise the rod and wheel 183 upward again into thesolid-line positions shown in FIG. 38. Depression of flap 182 from theposition shown in FIG. 38 to that of FIG. 39 will move downward theplunger stem 180 and the piston 188 carried by such plunger near theupper end of stem 1-62. The head on the lower end of the plunger willmove from a position above aperture 189 in the side wall of stem 162 toa position below such aperture such as shown in FIG. 39. Such downwardmovement of the plunger will expel a small amount of liquid from thehollow of stem 162 past check valve 179 and discharge it throughaperture 178 in the bottom of the pressure head 13k. When wheel 183rolls off flap 182, compression spring 190 beneath plunger 180 willraise the plunger again until its lower end is above the aperture 189.Each time the wheel 183 passes over the fiap 182 during rotation ofbrush 2, the plunger 180- will be reciprocated downward to eject afurther increment of liquid through aperture 17 8.

The tank 152 can be filled through an aperture in closure plate when themachine is upside down. Such aperture can be closed by a plug 191.

I claim:

1. A floor polishing and scrubbing machine comprising a casing, aunidirectional motor mounted on said casing and including a drive shaftheld against axial movement relative to said casing and rotatable aboutan upright axis, floor-engaging means secured to the lower end of saiddrive shaft for rotation therewith, a floor-engaging pressure elementengageable with a substantially smaller area of the floor thanengageable by said floor-engaging means for applying localizedconcentrated pressure on the floor, and actuating means operable topress said floor-engaging pressure element against the floor while saidfloor-engaging means is being rotated by said drive shaft with a unitarea pressure exceeding the unit area pressure of said floor-engagingmeans against the floor.

2. A floor-polishing and scrubbing machine comprising a casing, drivemeans carried by said casing and including a drive shaft rotatable aboutan upright axis, floor-engaging means disengageably connected to saiddrive shaft for rotation thereby, a floor-engaging pressure elementengageable with a substantially smaller area of the floor thanengageable by said floor-engaging means and carried by saidfloor-engaging means for applying localized concentrated pressure on thefloor separate from said floor-engaging means, and control means carriedby said casing and movable relative to said floor-engaging means toactuate said floor-engaging pressure element to exert such localizedconcentrated pressure on the floor.

3. The machine defined in claim 2, in which the floorengaging meansincludes a hub and an annular member encircling said hub, said hub andsaid annular member being relatively movable elevationally, and thefioorengaging pressure element is located beneath said hub and inwardlyfrom said annular member.

4. The machine defined in claim 2, in which the control means includes acontrol member operatively connected to the pressure element and carriedby and movable relative to the floor-engaging means to eifect downwardmovement of the pressure clement relative to the floor-engaging means,and means carried by the casing and engageable with said control memberto effect movement thereof relative to the floor-engaging means.

5. The machine defined in claim 4, in which the control member ismounted on the floor-engaging means for limited rotation relativethereto, and the means carried by the casing include brake means foreifecting such limited rotation of the control member relative to thefloorengaging means.

6. The machine defined in claim 5, in which the control member is acircular plate located above the pressure element and the brake meansare engageable with the margin of said plate, and wedging meansengageable between the fioor-engaging means and said plate, operable byrelative turning of said plate and the floor-engaging means to move saidplate and the pressure element downward.

7. The machine defined in claim 4, in which the control member is acircular plate tiltable relative to the floorengaging means, and thecontrol means further in- 23 cludes a stem engageable by said plate whentilted to depress said stern for moving the pressure element downwardrelative to the floor-engaging means.

8. The machine defined in claim 2, in which the control member is aring, and thrust means connected between said ring and the pressureelement to effect downward movement of the pressure element relative tothe floor-engaging means by said thrust means in response to rotation ofsaid ring relative to the floor-engaging means.

9. The machine defined in claim 8, in which the thrust 10 means includesa tiltable thrust loop.

10. The machine defined in claim 8, in which the thrust means includes atiltable strut.

11. The machine defined in claim 2, in which the 15 24 floor-engagingpressure element is offset from the axis of the drive shaft.

References Cited UNITED STATES PATENTS 1,707,575 4/1929 Schooling 15-491,773,992 8/1930 Gillis 1549 2,300,138 10/1942 Steele 1549 2,728,9281/1956 Beeren l529 2,930,056 3/1960 Lappin 15-49 EDWARD L. ROBERTS,Primary Examiner U.S. Cl. X.R. 51-177

